Tests aquarium water for carbonate hardness (KH) or calcium. Each test kit includes reagent(s), glass test tube with cap, and easy-to-follow instructions. Number of tests varies depending on water conditions. KH/Carbonate Test Kit can be used to determine the proper dose of pH buffers. For use in fresh and saltwater aquariums. Calcium Test Kit allows you to easily and accurately measure calcium levels and maintain a healthy reef aquarium. Uses titration method, with easy-to-see color change for precise measurement. Measures calcium levels as low as 20 mg/L. For saltwater aquariums.

What is Carbonate Hardness?
Carbonate hardness (also known as alkalinity) is the measure of carbonate and bicarbonate ion concentrations dissolved in water. These minerals are present in municipal, well, and bottled spring water. The level of carbonate hardness in tap and bottled water depends on the source of the water and the treatment processes it has undergone. Carbonate hardness helps stabilize pH in the aquarium. An aquarium with a low kH level (50 ppm or less) will tend to be acidic. Aquariums with very low kH are subject to rapid pH shifts.

Directions for Testing Carbonate Hardness (KH):
Read thoroughly before testing. Do not allow test solution to get into aquarium.

To remove childproof safety cap: With one hand, push red tab left with thumb while unscrewing cap with free hand.

Rinse a clean test tube with water to be tested.

Fill the test tube with 5 ml of aquarium water (to the line on the test tube).

Add carbonate hardness test solution, one drop at a time, holding dropper bottle upside down in a completely vertical position to ensure uniformity of drops. After first drop is added, solution will turn blue.

Cap the test tube and invert several times after each drop. Keep count of the drops being added. Do not hold finger over open end of the tube as this may affect the test result.

The test is completed when the water in the test tube, after having been shaken, turns from blue to yellow. If you have difficulty discerning the color after the first drop of test solution is added, remove the cap from the test tube and while holding it over a white background, look down through the tube.

The carbonate hardness value is determined by the number of drops of the reagent that must be added to turn the water in the test tube to bright yellow.

Calcium Test Kit

Calcium is one of the most important elements in a reef aquarium. Reef invertebrates such as corals, crustaceans, mollusks, and even some types of encrusting algae need calcium to grow and remain healthy. Over time, calcium levels drop as invertebrates use calcium in aquarium water.

Why Test for Calcium?
Monitoring calcium levels is essential for keeping a successful reef aquarium. Reef organisms use calcium to build a calcium carbonate skeleton. Over time, as the calcium in the water is utilized, the calcium level will gradually drop. Calcium must be present for corals to grow. Even reef invertebrates such as crustaceans, mollusks, and encrusting algae, require calcium to grow and remain healthy. The calcium level drops as it is used by invertebrates or as it reacts with excess phosphate. Elevated phosphate precipitates calcium, rendering it unavailable to reef organisms. Phosphate enters the aquarium from tap water and as a byproduct of fish and invertebrate metabolism.

Directions for Testing Calcium:
Measures calcium levels as low as 20 mg/L.
Read thoroughly before testing. Do not allow test solution to get into aquarium.

To remove childproof safety cap: With one hand, push red tab left with thumb while unscrewing cap with free hand.

Rinse a clean test tube with water to be tested.

Fill the test tube to the line on the test tube with the water being tested.

Don't take the quality of your tap water for granted. If you draw your water from a well, nature may not be providing you the perfect balance. If you are using tap water from your municipal department, it likely includes minerals and additives.

Serious hobbyists know that the best way to measure the salinity and specific gravity of aquarium water is to use a refractometer. These precision optical instruments are incredibly accurate even at very low salt levels, and are equally easy to use.

Testing your water parameters is an important method of foreseeing problems in your aquatic ecosystem before they result in catastrophe. Luckily, tools that were once only accessible (and affordable) to advanced hobbyists have since become simpler.

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Aquarium Pharmaceuticals Test Kits Calcium Test Kit
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Good Product
Does what it needs to do with good accuracy. Good product for the money.
August 26, 2012

I have always liked their test kits. They are spot on!
Great value!
I have always liked their test kits. They are spot on!
February 26, 2012

Easy to use and accurate
I had been using a different product to test my calcium and alkalinity. Despite dosing with a buffer and a calcium additive my levels were always too low. I used API's products and it showed my alkalinity to be too high and my calcium too low. I encourage everyone to use API. They are a far superior product. They have made me a loyal customer for sure!!!
August 13, 2011

This is the gold standard
Every saltwater aquarist needs to test for KH and calcium. These kits are reliable and easy to use. I've been in the hobby for quite some time and these kits have proven themselves to me time and time again.
December 19, 2012

Description:
Choose the easier way to measure reef aquarium
alkalinity (buffer)Innovative new alkalinity titration test you can use with one handTest alkalinity levels in coral reef aquariums with greater ease Achieve accurate alkalinity titration test results with just one hand! ...